Dot matrix display

This is a Dot Matrix Scrolling Sign. A Dot Matrix Display has an 5x7 led matrix with 5 columns and 7 rows. The display is controlled by the ATMega328 microcontroller board. The rows are controlled by PORTB of the microcontroller, while PORTD puts the data on the columns to make the characters. The Dot matrix display used here is the LTR-747HR and is 0.7 inch (17.8mm) high.